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Using spectroscopic ellipsometry, the optical properties of the Bi[sub 3.25]La[sub 0.75]Ti[sub 3]O[sub 12] (BLT) thin films with different film thicknesses on platinized silicon substrates prepared by chemical solution methods have been investigated in the 400-1700 nm wavelength range. By fitting the measured ellipsometric parameter (ψ and Δ) data with a multilayer model system and the classical dispersion relation for the BLT thin films, the optical constants and thicknesses of the thin films have been obtained. Meanwhile, some degree of inhomogeneity (in the form of low density layers or surface roughness) has been found in the BLT thin films except for the thinnest film, which was homogeneous throughout its thickness. The multilayer model system became very complicated with increasing thickness. It indicated that the microstructure of the BLT thin films varied with increasing thickness. The refractive index n of the BLT thin films increases with increasing thickness, and on the contrary, the extinction coefficient k decreases with increasing thickness. The dispersion of the refractive index can be well explained by a single-term Sellmeier relation. [ABSTRACT FROM AUTHOR]

Abstract: (K,Na)NbO3 ferroelectric films were grown on LaNiO3 coated silicon substrates by RF magnetron sputtering. The conductive LaNiO3 films acted as seed layers and induced the highly (001) oriented perovskite (K,Na)NbO3 films. Such films exhibit saturated hysteresis loops and have a remnant polarization (2P r) of 23μC/cm2, and coercive field (2E c) of 139kV/cm. The films showed a fatigue-free behavior up to 109 switching cycles. A high tunability of 65.7% (@300kV/cm) was obtained in the films. The leakage current density of the films is about 6.0×10−8 A/cm2 at an electric field of 50kV/cm. [Copyright &y& Elsevier]

Pb0.7Sr0.3TiO3/La0.7Sr0.3MnO3 (PST/LSMO) thin film has been deposited on Si substrate by chemical solution deposition. Obvious changes in dielectric constant and loss as functions of frequency and magnetic field were observed in PST/LSMO thin film. By applying both dc bias electric and magnetic fields, apparent dielectric anomalies were observed in the 'butterfly-hysteresis' curves. These effects may be useful for practical application. The mechanism for the magnetocapacitance effects in PST/LSMO is rationalized by combining the Maxwell-Wagner capacitor model and the magnetoresistivity and magnetostriction of the LSMO. [ABSTRACT FROM AUTHOR]

Lead-free (Bi 0.5 Na 0.5)TiO 3 (BNT)-based piezoelectric materials, have a great potential for high-precision actuators' applications. In this work, the high-quality (0.94- x %)(Bi 0.5 Na 0.5)TiO 3 -0.06BaTiO 3 - x %NaNbO 3 (x = 2–10, BNT-6BT- x NN) thin films have been successfully deposited on Pt/TiO 2 /SiO 2 /Si substrates by sol-gel method. An ultra-high poling strain S pol value of 1.7% with a unipolar strain S uni value of 1.47% was reported in the BNT-6BT-6NN thin films. The coexistence of the ferroelectric phase and relaxor state was observed in the compositions of x = 2–8. Furthermore, the BNT-6BT-6NN thin films show more active domain switching compared to other compositions. It is demonstrated that the optimized strain responses in the BNT-6BT-6NN are attributed to a synergistic reaction of active domain switching and reversible electric-field-induced phase transition between the ferroelectric phase and relaxor state. Our systematic study demonstrates that the BNT-6BT- x NN thin films with an improved strain response are promising candidates for the applications of miniaturized actuators. [ABSTRACT FROM AUTHOR]

It has been reported that grain size has significant influence on the dielectric properties of barium strontium titanate (BST) thin films. In this paper we have proposed a multilayer structure in which BST layers are separated by thin MgO layers which are expected to function as barrier to atomic diffusion so that the grain size of BST could be confined. By simulation we have found that for a device with a coplanar/composite film/substrate configuration, the introduction of MgO can effectively change the dielectric constant of the composite while the tunability is not significantly affected, provided the amount of MgO is smaller than 25%. A prototype device was prepared to demonstrate the feasibility of this idea. By X-ray diffraction measurements it is revealed that BST and MgO coexist in the composite. The dielectric property of the composite film was determined and it was found that the film has a tunability of up to ~7% at 500 MHz and under an electric field of 13.3 kV/mm. [ABSTRACT FROM AUTHOR]

Compared to the bulky ceramic counterparts, antiferroelectric (AFE) thin films exhibit higher energy-storage performance. It has been demonstrated that the performance of the AFE thin films is strongly affected by the thickness. However, possible changes in the phase structures and microstructures accompanied by varying thicknesses have been less known, which makes it hard to fully understand the physical insight of the thickness effect. Herein, we fabricate a series of PbZrO3 (PZ) thin films by chemical solution deposition whose thickness is approximately proportional to the number of deposition layers, i.e., one to four layers with each layer of about 60 nm in thickness. The detailed structural characterization has been performed by using x-ray diffraction, a scanning electron microscope, and a transmission electron microscope. The films are composed of nanorods oriented normal to the films in which each nanorod maintains single crystalline though segmented by the horizontal interfaces between each of the two neighboring layers, suggesting nearly perfect epitaxy during multilayer growth. The multidomain state is found in three-/four-layer PZ thin films while the one-/two-layer PZ films always present a monodomain state. Meanwhile, incommensurate phases with different modulation periods have been observed in the four-layer PZ films. By comparing the as-observed structural features with the measured electrical properties of different films, it seems that microstructural evolution with the film thickness should not be negligible in evaluating the structure–property relation of PZ-based thin films. [ABSTRACT FROM AUTHOR]

We report on a novel ferroelectric/gyromagnetic ferrite layered composite thin film with two degrees of tuning freedoms. The structure was prepared by layered growth of Y 3 Fe 5 O 12 (YIG) ferrite, LaNiO 3 (LNO) electrode and (1 0 0) orientated Pb 0.4 Sr 0.6 TiO 3 (PST) ferroelectric films on Si substrates by RF magnetron sputtering. LNO not only exists as an electrode, but also provides a buffer layer for the orientation growth of PST film. The PST/YIG composite thin films exhibited large magnetic tunability of μ r (92.1%@600 Oe), low FMR linewidth (ΔH) of 160.7 Oe@9.1 GHz and high electrical tunability (η) of 75%@360 kV/cm, which shows potential applications in magnetically and electrically tuning devices. [ABSTRACT FROM AUTHOR]

High-quality Yttrium iron garnet (YIG) films with crack-free surface and improved magnetic performance were grown on platinum (Pt)-buffered Si substrates by chemical solution deposition technique. The saturation magnetization of obtained YIG films can reach 124 emu/cm³, which was the 88% theoretical value of YIG single crystal. The effects of annealing condition were also discussed. When annealed at 750°C for 1 h, YIG films showed a very small coercive field of 12 Oe and the peak-to-peak ferromagnetic resonance linewidth can be as low as 95 Oe at 9.10 GHz. The results demonstrated that YIG films prepared on Pt-buffered Si substrates can be beneficial to the application of YIG films to integrated devices. [ABSTRACT FROM AUTHOR]

In this work, Pb 1−3 x /2 La x ZrO 3 (x = 0–0.12) (PLZ- x) antiferroelectric thin films were fabricated on Pt(111)/TiO 2 /SiO 2 /Si substrates using chemical solution method. Smaller cations (La3+) and vacancies were introduced into A-sites of perovskite structure to construct chemical pressure. According to phenomenological theory, chemical pressure can increase the energy barrier between antiferroelectric (AFE) and ferroelectric (FE) phase, and enhance antiferroelectricity of the system. As a result, a large energy storage density (W re) of 23.1 J cm−3 and high efficiency (η) of 73% were obtained in PLZ-0.10 films, while PLZ-0 films displayed lower W re (15.1 J cm−3) and η (56%). More importantly, PLZ-0.10 films exhibited an excellent cycling stability with a variation of ˜2% after 1 × 108 cycles. The results demonstrate that heavily La-doped PbZrO 3 films with high energy storage density, high efficiency and excellent cycling stability can be considered as potential candidates for energy storage applications. [ABSTRACT FROM AUTHOR]

Utilizing temperature and magnetic field dependent dielectric spectroscopy, two different dielectric relaxation processes, both accompanied with prominent positive magnetodielectric (MD) effects, were observed in Pt/BiScO3-PbTiO3/La0.7Sr0.3MnO3 (Pt/BSPT/LSMO) heterostructure. An equivalent circuit model is established to quantitatively describe the relaxation data well. The simulation results elucidated that one relaxation process can be attributed to magnetic order associated BSPT/LSMO interfacial relaxation with abnormal dynamics feature. Another one is due to the external contact interface contributions. Both relaxation dynamics can be tuned, via magnetic field controlled localization of free interfacial charges, to induce MD effects in BSPT/LSMO interfaces and nonmagnetic Pt/BSPT contacts. [ABSTRACT FROM AUTHOR]

Highly (001)-oriented pure PbZrO 3 (PZO) films and Sn-substituted PZO films are deposited on (001)-LaNiO 3 buffered SiO 2 /Si substrates by RF magnetron sputtering. Different Sn-substituted PbZrO 3 films (PbZr 1-x Sn x O 3 , x = 0%, 3%, 5%, 10%) with orthorhombic anti-ferroelectric phase are fabricated. The effects of Sn substitution on structure and energy performance have been investigated in detail. The switching electric fields are enlarged and energy loss is lowered by Sn substitution. Recoverable energy density (Wr) of 14.8 ± 0.2 J/cm 3 and energy efficiency (η) of 71.2 ± 0.5% at 900 kV/cm are obtained in 5% Sn-substituted PZO film (~ 360 nm). Furthermore, with thicker thickness of ~ 650 nm, Wr and η can be further improved. The Sn-substituted PZO film is believed to be an improved material for applications in energy storage systems and 5% Sn-substituted PZO film exhibits the highest Wr and η in this work. [ABSTRACT FROM AUTHOR]

The La 0.7 Ca 0.3 Mn 1−x Fe x O 3 (LCMFO: 0≤x≤0.10) thin films were synthesized by chemical solution deposition process on Si substrates. The structure, magnetic and transport properties have been investigated systematically. With the increase of Fe ion doping concentration, from x=0 to x=0.10, no apparent structural change was observed. While, the magnetization and Curie temperature were reduced dramatically, from 168 emu/cm 3 and 231 K for x=0–18 emu/cm 3 and 81 K for x=0.10, indicating that Fe ion suppressed the double-exchange mechanism and enhanced the anti-ferromagnetic ordering. Meanwhile, the resistance was very sensitive to Fe ion doping and an enhanced magnetoresistance (−94%) was observed in the sample of x=0.05. [ABSTRACT FROM AUTHOR]

SrRuO 3 (SRO) thin films were grown on SiO 2 /Si substrates with different thickness of LaNiO 3 (LNO) seed layers by RF magnetron sputtering. Effects of LNO thickness on the grain orientation, surface morphology, magnetic behavior and electrical transport properties of SRO films were investigated. The orientation of SRO films transformed from (110) pc to (001) pc and the residual stress was released gradually with increasing the thickness (pc refers to the pseudo-cubic unit cell of SrRuO 3 ). SRO films with higher orientation grown on LNO exhibited more flat surface, higher saturation magnetization, and lower coercive field. The magnetic anisotropy was enhanced on thicker LNO due to the different states of residual stress. In addition, the temperature dependence of resistivity was promoted by the microstructural disorder. (110) pc -oriented SRO monolayer electrode and (001) pc -oriented SRO/LNO300 bilayer electrode own low room temperature sheet resistance of 0.38 Ω/□ and 0.26 Ω/□, respectively. The results indicate that the controllable SRO films can be used as not only good bottom electrodes but also promising templates to control the crystallographic orientations of various other perovskite-based functional materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • The superior energy storage properties of Pb 0.925 La 0.05 Zr 1- x Ti x O 3 antiferroelectric thin films in Zr rich were obtained. • In Zr-rich region, the saturation polarization strengthens of PLZT with increasing Ti content due to change of ion-radius, and the switching field decreased which means the enhancement of ferroelectricity. • The co-doped PLZT films possessed higher breakdown strength, which greatly optimized the energy storage properties. • The high recoverable energy density of 49.7 J/cm3 and efficiency of 54% were obtained in the Pb 0.925 La 0.05 Zr 0.985 Ti 0.015 O 3 film. Pb 0.925 La 0.05 Zr 1- x Ti x O 3 (PLZT, x = 0.5%∼5.5%) thin film were fabricated on Pt(1 1 1)/TiO 2 /SiO 2 /Si substrates by sol–gel method. In the Zr-rich region, the saturation polarization strengthens with increasing Ti content due to the change of ion-radius. On the other hand, the switching field decreases, which means the enhancement of ferroelectricity. The phase structure and polarization of the films can be tuned by a small amount of Ti doping, and then the energy storage characteristics of the thin films can be modulated. The results showed that a large energy storage density (W rec) of 49.7 J/cm3 and efficiency (η) of 54% were achieved in the x = 1.5%. Moreover, the x = 1.5% sample displayed excellent cycling stability up to 1 × 106 cyclings, which demonstrated that La and Ti co-doped films can be considered as potential candidates for future energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract: We report the fabrication of Pb0.4Sr0.6TiO3 thin films with different microstructures and dielectric responses deposited on LaNiO3 buffered silicon substrate via the RF magnetron sputtering method with various deposition powers from 40W to 120W. Effects of the power on deposition rate, orientation, surface morphology and dielectric response were investigated. X-ray diffraction patterns indicated that the crystal orientation of thin films changes from (110) preferential orientation to random orientation with decreasing power, and finally to perfect (100) orientation. Moreover, the thin films prepared at lower power show more homogeneous grain size distribution and denser microstructure. The capacitance–voltage analysis revealed that the films deposited at lower powers show larger dielectric response and better tunability performance. Especially, large dielectric constant and tunability of 947 and 80.88% (@400kV/cm), respectively, were obtained under a deposition power of 40W. [Copyright &y& Elsevier]

This investigation presents a simple approach to realize the low temperature crystallization of Pb0.4Sr0.6TiO3 thin films at 400 °C by taking advantage of well controlled lead excess and kinetic-driving-force compensated thermodynamics crystalline via sputtering deposition. The thin films prepared at low temperature show fine-grained micro-structure because of the suppressed grain growth, furthermore, the intrinsic dielectric response can be modulated by the distinct level of crystallinity. The film processed at 450 °C exhibited a dielectric constant of 435 and high figure merit of 130 at 400 kV/cm, superior ferroelectric property, and stable performance with temperature and frequency. [ABSTRACT FROM AUTHOR]

Polarization switching and energy storage properties of highly (100) oriented antiferroelectric (AFE) (Pb,La)(Zr,Ti)O3 thin films (≤250 nm) deposited via a sol-gel process with both LaNiO3 and Pt top electrodes were investigated. By using LaNiO3 top electrodes, the energy density as well as energy efficiency can be enhanced by 4.6 J/cm3 and 11%, respectively. Furthermore, the films with LaNiO3 top electrodes are more capable of providing high energy density over a wide temperature regime above room temperature compared to Pt. This work clearly highlights that oxide top electrodes can greatly improve the energy storage performance of antiferroelectric thin film capacitors. [ABSTRACT FROM AUTHOR]

PbxSr1-xTiO3 ( PST) thin films with the ratio Pb/Sr = 40/60 were deposited on silicon substrate with Pt or LaNiO3 ( LNO) bottom electrodes by radio frequency magnetron sputtering followed by a postannealing treatment. The structural and microstructural analyses were performed and a perovskite phase was obtained whatever the nature of the bottom electrodes and even at a low temperature (450°C). The optimal annealing temperature is 650°C at which the films have a dense and fine microstructure. For electrical characterization the different top electrodes ( Pt and LNO) were used. In both cases, we demonstrate that PST films present excellent performances in terms of dielectric properties and in particular, the tunability and Figure of Merit. A large tunability (57% at 400 kV/cm) and low dielectric losses (1.4%) were measured at 10 kHz for Pt/PST/Pt structures postannealed at 500°C. For LNO/PST/LNO structures, postannealed at 650°C, the improved tunability (≈80%) and low loss factor (≈2%) were obtained. Prospects of PST as an alternative to BST for tunable applications with a real potentiality of monolithic integration with silicon, in terms of thermal budget, are considered. [ABSTRACT FROM AUTHOR]

PbZr0.35Ti0.65O3 (PZT), PbZrO3 (PZO), and PZT/PZO ferroelectric/antiferroelectric multilayer films were prepared on a Pt/Ti/SiO2/Si substrate using the sol–gel method. Microstructures and physical properties such as the polarization behaviors, leakage current, dielectric features, and energy-storage characteristics of the three films were systematically explored. All electric field-dependent phase transitions, from sharp to diffused, can be tuned by layer structure, indicated by the polarization, shift current, and dielectric properties. The leakage current behaviors suggested that the layer structure could modulate the current mechanism, including space-charge-limited bulk conduction for single layer films and Schottky emission for multilayer thin films. The electric breakdown strength of a PZT/PZO multilayer structure can be further enhanced to 1760 kV/cm, which is higher than PZT (1162 kV/cm) and PZO (1373 kV/cm) films. A recoverable energy-storage density of 21.1 J/cm3 was received in PZT/PZO multilayers due to its high electric breakdown strength. Our results demonstrate that a multilayer structure is an effective method for enhancing energy-storage capacitors. [ABSTRACT FROM AUTHOR]

Abstract: This investigation presents a novel method to prepare Pb0.4Sr0.6TiO3 thin films crystallized at relatively low temperature with different microstructures and enhanced tunability performance on LaNiO3 buffered SiO2/Si substrates. The incorporation of oxygen during the ex-situ RF magnetron sputtering unusually changes the microstructure of the films and remarkably improves the tunability because of the modulated dielectric constant with and without electric field. The dielectric response versus the DC electric field analysis revealed that the tunablity increased from 61.6% to 73.4% at ±400kV/cm with increasing content of oxygen while the loss factor retained relatively low, suggesting the film could be one of the promising candidates for the microwave tunable devices compatible with Si integrated circuits. [Copyright &y& Elsevier]

La 0.7 Ca 0.3− x Sr x MnO 3 ( x =0, 0.10, 0.15, 0.25 and 0.30) thin films were prepared by the sol–gel method on Si substrates. The structural, magnetic and transport properties were systematically studied. All the LCSMO thin films crystallized perfectly with a random crystalline orientation. The films show strong coupling between lattice and physical properties. With the increment in x , the lattice parameter increases, the magnetic properties are enhanced, and the T c increases monotonically from 235 K to 343 K. Resistivity is dramatically decreased with Sr dopant. The temperature corresponding to the MR maxmium value is close to that of the T MI for LCMO, while there was no peak value for Sr doped thin films in this temperature range. [ABSTRACT FROM AUTHOR]

The effect of residual stress on energy storage property was investigated for a series of PbZrO3 thin films on SrTiO3 and Si substrates. Compressive or tensile residual stress influences the critical electric field EA for the ferroelectric-to-antiferroelectric phase transition, thus for films with (110)/(101) orientation, energy density W of films on SrTiO3 is 38% larger than films on Si; in contrast, (001)-oriented PbZrO3 films on SrTiO3 show slightly smaller W compared to films on Si. We conclude that the different responses of W to stress are related to the different constrain states in films with different orientations. [ABSTRACT FROM AUTHOR]